1. Field of the Invention
This present invention relates to wheeled, transportation vehicles that operate on roadways or off road surfaces. The field spans from automobiles to trucks to farm tractors to construction vehicles to bicycles.
2. Description of the Prior Art
Essential traits of transportation devices include safety, comfort, convenience, and efficiency in the context of the way people's homes, work places, and other destinations are distributed Additionally, a successful product must not neglect the need to be appealing to prospective buyers. Automobile design has met such a list of requirements so well that cars have long been the prevailing choice of the public. Clearly there are many safety problems. Convenience is deteriorating with crowded roads and parking space. Efficiency is a problem of more or less severity depending on availability of fuel, and well known oil resource limitations indicate a future that looks difficult for the present automobile concept.
Electric vehicles have some promise. Domestic coal supplies are much more adequate than oil, so the use of this fuel in electric power generation is a practice that can continue for many years, even with expanded loads that result where the electric power is used to charge batteries that run electric vehicles. Simple adaptation of the present automobile designs to electric power is not a very satisfactory solution since the electric systems are limited in energy capacity. A more complete solution involves a completely new vehicle concept, where greater efficiency serves to enhance driving distance for a set of charged batteries. As far as possible, this complete solution should also improve safety and convenience.
A suggested answer to the problem comes from observation that over 95% of cars on the road have only one driver. Most car pool lanes are very lightly used, suggesting that drivers value their independence very highly. The most critical need is to alleviate the situation at commuting times where the percentage of single car riders is even higher. This leads to a search for a satisfactory single occupant vehicle. This does not have to be exactly a single rider, that is, a tandem rider arrangement would seem to offer some flexibility. If this can be half as wide as the conventional car, there are some very important advantages to be gained. Such advantages could include alleviating congestion and reduction in air drag. A design also needs to respond to driver discomfort with riding at a low level relative to other cars and trucks on the road, where poor visibility both is an irritation and a cause of hazardous situations. An electric vehicle design can go only part way toward this goal by judicious weight distribution, where very heavy batteries are placed to ride close to the ground.
In looking for alternatives one can examine other vehicle forms for ideas. Motorcycles and bicycles operate on very different dynamic principles. Farm tractors have utilized a tricycle configuration. Construction vehicles expand on steering possibilities. Forklift trucks have wheel base arrangements like automobiles running in reverse.
Large semi-trucks use tractor and trailer arrangements, where a hitch connects the two parts. The tractor is conceptually the same as the common automobile. The trailer is like a trailer pulled by an automobile. The arrangement appears to be worked out to distribute loads on the wheels. These hitches are two axis joints that allow tractor and trailer to turn independently and allow tractor and trailer to follow uneven surfaces. These are not configured to enhance roll stability of the rig since the two axis joint is arranged with the pitch axis fixed to the tractor and the yaw axis fixed to the trailer. When the tractor is turned at a right angle with respect to the trailer, the pitch axis of the joint is aligned with the roll axis of the trailer. Therefore, no roll stabilizing torque can be transferred from the tractor to the trailer. The mechanism operates to provide less roll stabilization as turning conditions cause a need for more stabilization. It appears that this design concept depends on the inherent stability of the heavy load and a need for only gradual turns at higher speeds.
Articulated vehicles have been developed for off road use. Those known appear to use the articulated arrangement to enable different parts of the vehicle to hold contact with irregular ground surfaces.